1. Rated power deviation of heating pipe: power deviation range of finished product + 3% - 6%.
2. Leakage current: the leakage current and the leakage current after water pressure and seal test under the working temperature shall not exceed 0.4ma per kilowatt.
3. Electrical strength:
When the heating tube is cold, the element shall be able to withstand ac2000v, the setting current is 0.3mA, lasting for 1 minute, without breakdown or flicker. Under the working temperature, the element shall be able to withstand ac1250v, with the setting current of 2mA, lasting for 1 minute, without breakdown or flicker. After the dry burn test, the components shall be able to withstand ac1800v, set current 5mA, no breakdown or flicker for 3 minutes.
4. Uniformity of heating element: the heating part of the element shall be uniform, and the surface temperature deviation shall not be greater than ± 10%. The symmetrical deviation of the length of the outgoing bar in the pipe shall be less than 2mm.
5. Insulation resistance: it must be greater than 50 megohm in cold state and not less than 2 megohm in hot state.
All of the above five points need to be tested before the application of heating tube.